System of electrical distribution.



Patented Sept. 26, I899.

L. B. STILLWELL.

SYSTEM OF ELECTRICAL DISTRIBUTION (Application filed May 24, 1899.-

2 SheetsSheet l.

(N0 Model.)

INVENIOR ATTOHNE).

W/ I NE 8858 No. 633,920. Patented Sept. 26, I899. L. B. STILLWELL.

SYSTEM OF ELECTRICAL DISTRIBUTION.

x Appliuation film! May 24, 1899.) (No Model.) 2 Sheets-Shuat 2,

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UNITED STATES PATENT, @FFICE.

LEWIS B. STILLIVELL, OF NIAGARA FALLS, NEIV YORK.

SYSTEM OF ELECTRICAL DISTRIBUTION.

SPECIFICATION forming part of Letters Patent No. 633,920, dated September 26, 1899.

Application filed May 24:, 1899. Serial No. 718,090. (No model.)

To ctZZ whom, it ma l concern:

Be it known that I, LEwIs B. STILLWELL, a citizen of the United States, residing at Niagara Falls, in the county of Niagara and State of New York, have invented a new and useful Improvement in Systems of ElectricalDistribution, of which the following is a specification.

Myinvention relates to systems of electrical distribution, and particularly to means employed for protecting such systems from i11- juries resulting from short circuits and overloads.

The object of my invention is to provide an effective means for localizing the interruption of service which in electric-power plants is likely to be caused by a short circuit or overload upon one of the branch circuits of the system.

In large systems of electrical generation and distribution it is usual to transmit the electrical energy from the generating-station to a plurality of substations, and from each substation energy is distributed for lighting and power purposes in various directions by local feeder-circuits.

If circuit breakers or fuses of ordinary types be used, a short circuit upon one of the feeder-circuits radiating from a substation will frequently result in a total interruption of service from that substation and will sometimes result in a total interruption of the service from all substations which are supplied through the main transmission-circuit, since it is liable to open not only the circuitbreakers or fuses in the feeder-circuit first affected, but also to open the circuit-breakers or fuses through which the entire amount of power delivered to the substation is conveyed and in some cases even the circuit-breakers or fuses at the main station.

In the case of circuit-breakers of the ordinary type, even where dash-pots are used for delaying the opening movement, the time which elapses after the short circuit is estab lished before the circuit-breaker acts depends upon the quantity of current which flows in the circuitt. e., upon what is ordinarily termed the severity of the short circuit.

In cases where my present invention is employed the time which must thus elapse is absolutelyindependent of the severity of the short circuit. It is thus made possible to open with certainty any branch or feeder which may become short-circuited without any risk of cutting off the supply of power from other branches or feeders of the system.

My invention is illustrated in the accompanying drawings, in which Figure 1 is a diagrammatic view of a. circuit-breaker constructed in accordance with my invention and in closed position. Fig. 2 is a view corresponding to Fig. 1, but showing the circuit-breaker open. Fig. 3 is a diagram of a system of distribution embodying my invention.

Referring now particularly to Figs. 1 and 2 of the drawings, 1 is an electric conductor forming one side of a circuit to be protected and including the primary winding 9 of a transformer 3, one terminal of the secondary winding i of this transformerbeingconneeted to one terminal of a coil 5 of a magnet 6. The armature 7 for the magnet is pivotally mounted upon a suitable bracket or other support 8 and has an arm 7 extending beyond the point of support, so as to engage with a pin 9, projecting laterally from a substantial] y vertical rod 10. connected at its upper end to a holdingpawl 11, the free end of which, when in the position shown in Fig. 1, engages with one of the teeth of an escapement-wheel12 of a clock-train 13. The pawl is normally held in this position by means of gravity and the action of a coiled spring 10", interposed between a portion of the bracket 6 and an adjusting-nut 10 on the lower end of the rod 10. The clock-train 18 when free to move may be operated by a spring or weight and regulated in any wellknown manner, so as to rotate at a certain definite speed a wheel or disk 14, the body of which is preferably formed of insulating material and is provided with a con d u ctin g-strip 15, which extends over a portion. of its periphery. A contact finger or brush 16 engages with the periphery of the wheel 14c and constitutes the terminal for one end of the trans former secondary l and also for one end of the coil 17 of a magnet 18. The other end of The rod 10 is pivotally the coil 17 and one end of the coil 5 are suitably connected together and to the rim 15 of the wheel 14 by any suitable means.

The circuit-breaker proper may be of any suitable form adapted for automatically opening an electric circuit.

I desire it also to be understood. that my invention is also intended for use in connection with polyphase circuits of any practical In the present case I have shown it as comprising a pair of stationary terminals 19, a bridging movable terminal 20, toggledevers 21, a handle 22 for moving the member 20 into engagement with the terminals 10, and a latch 23, constituting an extension of the armature 94 of the magnet 18.

It will be understood from the construction here illustrated and described that so long as the parts are in the position shownin Fig. 1 and the current in the circuit does not rise above the amount for which the clocktrain-releasing mechanism is adjusted there will he no movement of the clock-train or of the circuit-breaker. If, however, the current increases to such an amount asto cause the magnet 6 to exert a pull upon the armature 7 sufficient to overcome the action of gravity and that of the coiled spring 10, the pawl 11 will be raised out of engagement with the escapement-wheel 12 and the clock-train will operate to rotate the wheel 14-. So long as the brush 16 is in contact with the rim 15,

however, the coil 17 of the magnet 18 will be I sarily be compelled to traverse the coil 17 of the magnet 18, and the latter will attract its l armature 2 1, and thus withdraw the latch 23 and permit the circuit-breaker to open, as is indicated in Fig. 2.

Referring now to Fig. 3 of the drawings, the main generating-station or source of power is represented by an alternating-current generatorA, and the main transmission-conductors 1 and 1 are protected from short-circuits and overloads by the circuit-breaker mechanism B, having an operative connection with the conductor 1 by means of the transformer 3, the same as is indicated in Figs. 1 and 2. G and D represent two substations, respectively provided with circuit-breaking apparatus C and D similar to that already de scribed, and from each station subfeeders to any desired number may extend in various directions for supplying either light or power, or both, for local consumption. Two of such circuits 0 c and c c are shown as branching from the substation C. The subteeder c is provided with a circuit-breaker C and the subfeeder c with a circuit-breaker G which may be the same in construction and mode of operation as already described. The number of substations and the number of subfeeders branching from-anyone or all of them may be anything desired, and my invention is therefore not limited in this regard.

number of phases and that the protecting means described may be connected to each side of each circuit or to two conductors of a three-phase circuit.

In utilizing myinvention in a system such as is generally indicated in Fig. 3 the time element of the circuit-breaker will open only atthe end of a predetermined interval of time after the time-measuring mechanism begins to operate.

In order that the opening of each circuit may be rendered independent of all the others, I propose to so set the circuit making and breaking element of the time-measuring mechanism or device-this element, as shown, being the wheel 11pertaining to each circuit-breaker that the time period which will elapse before the breaker will act will be of different length from that of any other controlling or dependent circuit. For example, each of circuit-breakers C and 0 maybe set to open at an interval of, say, two seconds after the occurrence of a local short circuit,

circuit-breakers C and D after an interval. of four seconds, and circuit-breaker B after an interval of six seconds. It will thus be seen that should the trouble occur at any point other than at the main station the particular cireuit where the trouble occurs will be opened before the circuit-breakers at other points which are set for a greater time limit will have an opportunity to open.

It will be understood that my invention is not limited to any specific time-measuring device or to any particular type of circuitbreaker, and that where I have illustrated and described magnets and arinatures solenoids and movable cores may be employed.

I claim as my invention 1. In a system of electrical distribution c011- sisting of a main supply-circuit and two or more subordinate or distributing circuits which receive energy from the main circuit, an automatic circuit-opening device control ling the main supply-circuit, and an automatic circuit-opening device controlling one or more of the subordinate distributing sup ply-circuits, these circuit-breakers being severally provided with time-measuring mechanisms so adjusted with reference to each other that in case of a short circuit upon a subordinate circuit, the circuit-breaker controlling the subordinate distributing-circuit must operate before the circuit-breaker con= trolling the main circuit operates.

2. In a system of electrical distribution, a main supply-circuit and a plurality of subordinate distributing-circuits, in combination with a circuit-breaker for each circuit and a time-measuring controlling device for each circuit-breaker, each of said devices corresponding to a subordinate circuit being set to insure the opening of its breaker before the breaker of any (lOlllll'liLLlllg circuit can be :1, predetermined interval of time after the be 10 automatically opened. gii'ining of an excessive [low of current in its 3. In a system of electrical distribution, 1L circuit. main supply-circuit and one or more subor- In testimony whereof I have hereunto sub- 5 dinate distributing-circuits supplied thereby, scribed my name this 16th day of May, 1899. in combination with a cireuit-brenker in each L. B. STILLVELL. of said circuits and time-measuring mechanlVitnesses: ism for each circuit-breaker provided with means for insuring the opening of the breaker M. WILSON, F. L. LovELAeE. 

